Electrical switch.



sure decreasing as the distance' from the bend increases.

The bars 1 and 3 being secured yith their faces in actual contact, theknife bar 7 enteringl between the two halves of the switch, in bringingthe bars 1 and 2 together into the position shown in Fig. 3, produces aresult which may be Idescribed as rocking the bar 8 upon the bar 1, thatis, the point of divergence from contact is transferred toward the base4 as the knife bar 7v enters between the rjaws of the switch.

The two bars 1 and 3 may be considered as levers having a measure offlexibility. Their fulcrum point is the point of divergence fromcontact. As the knife bar 7 enters between the two bars 3, the bars 1and 3 are bent and the point of contact travels backward toward thebase. ln consequence the pressureof the springr against the knife bar isnot being greatly reduced as it passes inward between the jaws. Fromthis it results that there is a better electrical contact between theknife bar and the jaws. The same rocking action, or transference of thefulcrum point between the supporting bar 2 and the spring bar 1 takesplace as has been described as occurring between the bars l and 2. Thisresults in a much more equal pressure upon the knife bar at'all pointsthan if these members were all actinginde- Apendently, without anyeffect upon each other. y y

lf the knife bar 7 should happen to not be parallel with the true planesof the jaws, the j aws` are sumciently flexible to adjust themselves tothis and make a true and large contact in spite of the twist of theknife bar.

Securing the two bars 1 and 3 -with their faces in close and unyieldingcontact at their outer ends, is superior to an open bend, for manyreasons. As above pointed out it results in a transference of thefulcrum point along the bars so as to keep this fulcrum point near theentering blade at all times, thus making the pressure exerted by thebars upon the blade more nearly equal at all points. This produces asuperior contact than would follow were the two bars connected by anopen bend, as in the latter case the pressure upon the blade would.rapidly decrease as it passed inward between the jaws. Arcing, whichalways occurs to a greater or less extent upon opening and closing aswitch, always acts upon that portion where the make and break occurs.This switch. thus reducing the cross section of the arm, Second, bannealing the material of the switch and estroying its resilientqualities. A s, in my construction, the point of arcing is confined tothat portion in which the two parts of the jaw are secured with theirfaces in Contact, the material throughout the entire area affected byarcing, acts only as a physical or binding connection between the jawsand not at alll as a spring'. For this function its area is so greatthat a large reduction in area would still leave it with ample strength.As to the effect of the annealing action, this will have no effect uponthe spring action of the jaws, as the area affected in this way at notime acts as a spring, this action being confined to the body of thejaws sufficiently removed from the arcing zone to be unaffected bythearcing.

` What 1 claim as my invention is: 1. A jaw member for electricalswitches comprising two spring-like members secured together at one endwith their faces in contact, one of said members being secured at. itsopposite end to av support and the other constituting the contactmember, said members being differently curved to normally hold their major part separated, and adapted to have said normallyseparated partsbrought gradually into contact as the switch passes over the Contactmember.

2. 1n an electric switch, in combination, a base, a pair of spring armssecured at one end to said base and projecting therefrom in thesame'ldirection but in separated relation, a spring arm secured to andwith a side surface in cont-act with the inner surface of the outer .endof each of said yfirst-mentioned arms, the arms so connected being givenan initial curvature acting to separate them as they extend away fromtheir point of union when unrestrained but permitting bringing saidsurfaces into contact by the pressure of the movable member of theswitch inclosing.4

3. A jaw member for electric switches comprising two spring-like armssecured toj gether at one end with side faces in close contact, thesecured ends of said arms being' curved to normally slightly divergetheir free portions away from their secured ends,

the free end of one of said armsbeing longer than the other, and meansfor securing said extended end to a support. y

4. In an electric switch, the combination with a base, of spring armssecured to the base and projecting in the same direction from the basebut in separated relation,

rst mentioned spring arms and extendingy fixed my signature at Seattle,Washington, backvxrd therebeween, the imctedspring this 6th day of July,1911. arms eing curve to norma 'verge away from theirV point ofconnection, said inner O' N' WISWELL 5 set of arms serving as thecontact members Witnesses: of thecomplemental part oie-the switch. H. L.REYNOLDS,- In testimony .whereo I have herento af- R. C. PoLLn'rr.

